The invention relates to a spacer or valved chamber for delivering aerosol medication from an MDI canister in a dispenser ("boot") supplied by the manufacturer to a patient, through a hand-held chamber operated by the patient, and particularly to an inexpensive collapsible, disposable valved chamber.
MDI drug canisters, which have been used since 1956, are sold with a "boot" that includes an actuator, a nozzle, and a mouthpiece. The patient can self-administer the MDI drug using the boot alone; however, the patient must place the mouthpiece of the boot in or near his/her mouth and inhale exactly when the MDI canister is actuated. This is difficult for some patients. Therefore, various suppliers have provided valved chambers that can be used in conjunction with an MDI boot. Such valved chambers may improve drug delivery by reducing the oropharyngeal deposition of the aerosol drug and by making synchronization of the MDI canister actuation with inhalation of the ejected medication less critical.
A commonly used valved chamber of this type is manufactured by Monaghan Medical Corporation, marketed under the trademark "AEROCHAMBER", and refers to U.S. Pat. Nos. 4,470,412 and 5,012,803. Another similar valved chamber of this type is marketed under the trademark "OPTICHAMBER", described in U.S. Pat. No. 5,385,140 (Smith).
The prior AEROCHAMBER device utilizes only an inhalation valve, so the patient must exhale before placing the device in his/her mouth. That presents a significant problem because it is difficult for many patients to initially perform the required sequence of (1) exhaling, (2) then immediately placing the chamber mouthpiece in his/her mouth, (3) then actuating the MDI canister to inject a medication plume into the valved chamber, and (4) then taking a slow deep breath and holding his/her breath for a few seconds. The prior OPTICHAMBER device provides both an inhalation valve and an exhalation valve, so that device need not be removed from the patient's mouth in order to use it.
A problem of the prior art is that the prior valved chamber devices are far too expensive to be considered disposable, and/or they are not at all collapsible or are insufficiently collapsible to be carried conveniently in a briefcase, vest pocket, or the like. U.S. Pat. Nos. 4,637,528 and 4,641,644 disclose aerosol inhalation devices that are partly collapsible, but not to a generally thin, flat configuration. U.S. Pat. No. 4,953,545 discloses a chamber that is disposable but not collapsible.
The retail cost of prior valved chambers described above typically is as much as nearly $20.00. This cost may be acceptable to patients having chronic conditions that require frequent use of MDI inhaler medication for a long period of time, provided the patients are willing to frequently clean such MDI inhalers. However, many patients need MDI inhaler medications for only a short period of time, in which case the high cost of the prior art valved chambers is very unsatisfactory, especially if a substantially lower cost alternative were available.
Thus, there is an unmet need for an improved valved chamber device which avoids the above mentioned problems of the prior art and provides a portable, light, reliable, inexpensive, disposable, collapsible, easy-to-use valved chamber for use with MDI inhalers. There also is an unmet need for an improved valved chamber device which is sufficiently inexpensive that it can be used as a disposable diagnostic dosing aid, temporary medication delivery aid, or teaching aid for instructing patients in the use of valved chamber devices.